Jigging is one of the oldest methods for concentrating ores and is still widely used. It is a gravimetric method of concentration which utilizes differences in the densities of wanted and unwanted materials to effect their separation. In jigging, water is strongly pulsed upward and downward through a suspended bed of particles. After sufficient pulsation, the top portion of the bed becomes an accumulation of lighter gangue, which can be rejected, while the lower portion contains the heavier enriched concentrate.
Typical jigs use a jig tank which is open at its top and bottom ends. The top of the jig tank includes a perforated, tapered, and inclined chute through which the material being separated flows to the tank. Oversized material is prevented from entering the jig tank by perforated screens, and caused to flow down the tapered portion of the chute to be discharged from the jig. The screen typically has a removable grate on top of it which acts as a containment grid for ragging material, which is usually spherically-shaped material that is heavier than the ore being processed and sized larger than the screen mesh. The ragging acts like a check valve when the jig is operating. Water pulsations within the jig lift the ragging up and off the screen and create a dilation of the bed of material above the screen. This puts particles in the bed in a state of suspension. Heavier particles within the bed progress downwardly into the ragging until they are finally able to pass through the screen. The particles settle within the tank until they are able to exit at the bottom through a valve.
The lower portion of the jig tank is angled inwardly to cause the heavier, concentrated material to flow to an outlet through which water and material having been concentrated flows. The jig tank is also provided with a source of make-up water, commonly referred to as hutch water, to replace water removed through the exit portion of the jig tank, and to fill the volume of water that is displaced by the piston on the power stroke.
One method of imparting the pulsating or oscillating motion of water within the jig tank is illustrated in our U.S. Pat. No. 4,849,097. There illustrated is a trapezoidal shaped jig tank the lower portion of which is angled inwardly to join with a vertically movable cone by means of a fluid-tight flexible diaphragm. The movable cone is mounted to a pivotal frame arm, commonly referred to as a walking beam, which is pivotally driven to generate pulsations within the tank.
This invention relates to alternate mechanisms and means for imparting oscillating or pulsation motion of water within a jig tank.
This invention relates to alternate mechanisms and means for imparting oscillating or pulsation motion of water within a jig tank.